Add a new IO_TLB_SIZE define instead open coding it using
IO_TLB_SHIFT all over.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Jianxiong Gao <jxgao@google.com>
Tested-by: Jianxiong Gao <jxgao@google.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

For SEV, all DMA to and from guest has to use shared (un-encrypted) pages.
SEV uses SWIOTLB to make this happen without requiring changes to device
drivers.  However, depending on the workload being run, the default 64MB
of it might not be enough and it may run out of buffers to use for DMA,
resulting in I/O errors and/or performance degradation for high
I/O workloads.

Adjust the default size of SWIOTLB for SEV guests using a
percentage of the total memory available to guest for the SWIOTLB buffers.

Adds a new sev_setup_arch() function which is invoked from setup_arch()
and it calls into a new swiotlb generic code function swiotlb_adjust_size()
to do the SWIOTLB buffer adjustment.

v5 fixed build errors and warnings as
Reported-by: kbuild test robot <lkp@intel.com>

Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
Co-developed-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Pull vhost fixes from Michael Tsirkin:
 "Fixes all over the place, most notably vhost scsi IO error fixes"

* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost:
  vhost scsi: Add support for LUN resets.
  vhost scsi: add lun parser helper
  vhost scsi: fix cmd completion race
  vhost scsi: alloc cmds per vq instead of session
  vhost: add helper to check if a vq has been setup
  vdpasim: fix "mac_pton" undefined error
  swiotlb: using SIZE_MAX needs limits.h included

The tbl_dma_addr argument is used to check the DMA boundary for the
allocations, and thus needs to be a dma_addr_t.  swiotlb-xen instead
passed a physical address, which could lead to incorrect results for
strange offsets.  Fix this by removing the parameter entirely and hard
code the DMA address for io_tlb_start instead.

Fixes: 91ffe4ad534a ("swiotlb-xen: introduce phys_to_dma/dma_to_phys translations")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

After merging the drm-misc tree, linux-next build (arm
multi_v7_defconfig) failed like this:

In file included from drivers/gpu/drm/nouveau/nouveau_ttm.c:26:
include/linux/swiotlb.h: In function 'swiotlb_max_mapping_size':
include/linux/swiotlb.h:99:9: error: 'SIZE_MAX' undeclared (first use in this function)
   99 |  return SIZE_MAX;
      |         ^~~~~~~~
include/linux/swiotlb.h:7:1: note: 'SIZE_MAX' is defined in header '<stdint.h>'; did you forget to '#include <stdint.h>'?
    6 | #include <linux/init.h>
  +++ |+#include <stdint.h>
    7 | #include <linux/types.h>
include/linux/swiotlb.h:99:9: note: each undeclared identifier is reported only once for each function it appears in
   99 |  return SIZE_MAX;
      |         ^~~~~~~~

Caused by commit

  abe420bfae52 ("swiotlb: Introduce swiotlb_max_mapping_size()")

but only exposed by commit "drm/nouveu: fix swiotlb include"

Fix it by including linux/limits.h as appropriate.

Fixes: abe420bfae52 ("swiotlb: Introduce swiotlb_max_mapping_size()")
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Link: https://lore.kernel.org/r/20201102124327.2f82b2a7@canb.auug.org.au
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

Compiler is not happy about one function prototype:

  CC      kernel/dma/swiotlb.o
  kernel/dma/swiotlb.c:275:1: warning: no previous prototype for ‘swiotlb_late_init_with_default_size’ [-Wmissing-prototypes]
  275 | swiotlb_late_init_with_default_size(size_t default_size)
      | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Since it's used outside of the module, move its declaration to the header
from the user.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Untangle the way how dma_direct_map_page calls into swiotlb to be able
to properly report errors where the swiotlb DMA address overflows the
mask separately from overflows in the !swiotlb case.  This means that
siotlb_map now has to do a little more work that duplicates
dma_direct_map_page, but doing so greatly simplifies the calling
convention.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

This splits the size parameter to swiotlb_tbl_map_single() and
swiotlb_tbl_unmap_single() into an alloc_size and a mapping_size
parameter, where the latter one is rounded up to the iommu page
size.

Suggested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

Pull virtio updates from Michael Tsirkin:
 "Several fixes, most notably fix for virtio on swiotlb systems"

* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost:
  vhost: silence an unused-variable warning
  virtio: hint if callbacks surprisingly might sleep
  virtio-ccw: wire up ->bus_name callback
  s390/virtio: handle find on invalid queue gracefully
  virtio-ccw: diag 500 may return a negative cookie
  virtio_balloon: remove the unnecessary 0-initialization
  virtio-balloon: improve update_balloon_size_func
  virtio-blk: Consider virtio_max_dma_size() for maximum segment size
  virtio: Introduce virtio_max_dma_size()
  dma: Introduce dma_max_mapping_size()
  swiotlb: Add is_swiotlb_active() function
  swiotlb: Introduce swiotlb_max_mapping_size()

This function will be used from dma_direct code to determine
the maximum segment size of a dma mapping.

Cc: stable@vger.kernel.org
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>